What does the Glow-worm F.20 fault code mean?

Your boiler has automatically shut down because it detected that the internal temperature has become too high, preventing it from overheating.

How much does it cost to fix Glow-worm error code F.20?

Typical repair cost for the Glow-worm F.20 fault is £100-280 including labour.

Check that your radiator valves are fully open to allow water to flow.

Safety switch-off – overheating temperature reached

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Each noise points to a different fault.

Work through these before the call-out.

Lockout fault with a reset-needed pattern.